This invention relates to lining materials containing curable resins, being materials in the form of tubular structures which are for use in connection with the lining of pipelines and passageways, especially underground sewers and the like.
The use of lining tubes which are resin impregnated, for lining sewers is now well known, the basic technology being disclosed in U.S. Pat. Nos. 4,009,063 and 4,064,211. These patent specifications disclose the nature of the processes and materials used in applying resin impregnated linings to underground pipelines and passageways. Basically, a tube of resin absorbent material is thoroughly impregnated with the resin, and whilst the tube so impregnated and is still flexible, it is urged against the pipeline or passageway surface to be lined, and then the resin is cured whereby a hard resin lining pipe having the absorbent material embedded therein is formed on the pipeline or passageway surface, completing the rehabilitation of same.
These methods, which are referred to sometimes as "cured in place" methods are practised widely throughout the world, and the processes are extremely successful.
There have been developments recently however to improve the processes and the materials, and such developments comprise the provision of resin systems which are quiescent or latent insofar as the resin which is used for the lining tubes will remain uncured for a long period of time, but can be cured selectively by the application of appropriate means, typically radiation, such as ultra sonic radiation, microwave radiation, light radiation or even heat radiation. The reason for producing latent resin systems for use in these processes is to enable the production of the lining materials at a substantial period of time before the materials are actually to be used in the lining operation. This means that the linings including the resin can be manufactured and stored and will eventually be orderable from a stock of the materials for each particular contract.
The present invention concerns mainly those lining tubes which include latent resin systems (although it can be applied where non-latent conventional and other resin systems are used), and where a large length of the lining material forms a stock, and sections can be cut off therefrom for particular jobs.
Recent developments related to the materials have provided that the layer of the tube which includes the resin is an extrudate of the resin mixed with reinforcing material such as fibres. The extrudate may be sandwiched between films or coatings in such lining tubes there is no layer which is "impregnated" with the resin but rather the resin mixture is a tactile mass which forms a curable layer.
When a lining structure is fabricated for a particular contract, the lining tube will be manufactured to the appropriate length, and is provided with appropriate end formations whereby the end of the lining bag is closed, to retain the resin therein, and is also provided with appropriate fastening devices to enable for example ropes to be connected thereto, whereby the lining material can be pulled into the pipeline or passageway to be lined, or, where it is everted into the pipeline or passageway, its progress can be controlled. In general therefore, the ends of the lining material are closed, and it is usual to provide special closure ends for the lining material.